An Italian Carabiniere stands close to a video in Rome's Rebibbia court during the Ustica trial, September 28, 2000. On the evening of June 1980 an airplane DC-9 of the now-defunct airline Itavia, crashed into Mediterrenean sea near the southern Italian island of Ustica on the evening of June 27, 1980 killing 81 people.

A missile caused a 1980 plane crash, according to a ruling by Italy's top criminal court this week.

An Italian court on Monday ruled that there was "abundantly" clear evidence that a stray missile hit and caused an Italian passenger plane to crash into the Mediterranean Sea in 1980.

The crash sparked outrage at the time, after it killed all 81 passengers and workers on board.

The court upheld a Palermo appeals ruling that Italian radar systems were not adequate in providing protection for the plane, and that the tragedy could have been avoided, according to Italian news agency LaPresse.

The latest ruling on the case will mean that the Italian authorities will have to compensate the victims' families from the tragedy.

For decades now it has been a mystery about what caused the Itavia DC-9 to crash as it went about its journey from Bologna to Palermo in 1980. There has been much debate and controversy surrounding the crash and deaths of the 81 people on board, but the latest ruling will provide vindication for those who have argued that a stray missile was to blame for the tragic accident.

Over the years conspiracy theorists have claimed all sorts of reasons why the plane went down, with some believing a bomb was on the plane, where as others believed that the plane had been caught in cross-fire during a military jet dog fight. Others have said a Libyan plane was the actual target but that the Italian passenger jet was hit in an accident.

However, throughout the past three decades French, United States, and NATO officials have repeatedly denied there being any military activity in the skies in that region on the night in question.